KR20120060838A - Process for producing propylene oxide - Google Patents

Abstract

The present invention relates to a mixture of (a) propylene, (b) one or more peroxide compounds, (c) one or more catalysts, such as titanium silicalite-1 (TS-1) catalyst and (d) a predetermined amount of solvent mixture A multi-liquid phase composition comprising the reaction mixture and a process for preparing propylene oxide; Wherein the solvent mixture comprises at least (i) one or more alcohols such as methanol and (ii) one or more non-reactive cosolvents; The solvent is mixed at a predetermined concentration; The non-reactive cosolvent has a different boiling point than the propylene oxide; The resulting propylene oxide product is partitioned in a high affinity solvent during the reaction. The process of the invention advantageously produces a waste stream with little or no significant amount of sodium chloride (NaCl).

Description

Process for producing propylene oxide

The present invention relates to a process for producing propylene oxide by reacting propylene and peroxide compounds in the presence of a catalyst such as titanium silicalite-1 (TS-1) catalyst and in the presence of a mixed solvent system. It is about.

In the production of propylene oxide, conventional methods in the prior art include reacting propylene with hydrogen peroxide to produce propylene oxide. The method is typically performed in one or more stages. See, for example, US Pat. No. 6,479,680; No. 6,849,162; No. 6,867,312; 6,881,853; 6,881,853; No. 6,884,898; No. 6,960,671; No. 7,173,143; No. 7,332,634; 7,378,536; And 7,449,590, all of which are incorporated herein by reference, disclose propylene oxide using hydrogen peroxide in the presence of a catalyst such as a titanium silicalite-1 (TS-1) catalyst and in the presence of a solvent such as methanol. It describes a method for preparing the same.

A problem in the production of propylene oxide using the above prior art methods is that the activity of the catalyst decreases over time. Typically, the TS-1 catalyst used under the process conditions of the prior art is inactivated with time and complete regeneration can only be achieved by firing.

Another problem with the prior art propylene oxide production process involves the use of methanol as a solvent for the process. Although methanol is an essential component of the peroxide reaction to obtain high activity, methanol is generally used in very excess. See, eg, literature; Clerici et al., "Epoxidation of Lower Olefins with Hydrogen Peroxide and Titanium Silicalite," Journal of Catalysis, 1993, 140, 71-83, describes methods representative of the TS-1 / H ₂ O ₂ epoxidation method. Where the methanol level used in the examples is approximately 97%. The use of excess methanol results in the formation of a single phase during the reaction, but suffers from the formation of byproducts from the reaction of propylene oxide with water solubilized with methanol and methanol in the organic phase. The use of large amounts of methanol also requires high energy consumption for the purification of products produced on large towers and industrial scale for propylene oxide production equipment.

In an attempt to increase the selectivity of the catalyst, another prior art method involves the addition of additional selectivity enhancing compounds to the reaction mixture. For example, in US Pat. No. 7,323,578, both continuous and batch processes for preparing oxiranes by reaction of olefins and peroxide compounds can be used, wherein the liquid phase of the reaction comprises water, one or more organic solvents, catalysts, And one or more compounds that increase the selectivity of the catalyst for the epoxidation reaction. Compounds that increase selectivity are selected from inorganic or organic bases, salts and their conjugate acids or bases, salts or mixtures thereof. However, US Pat. No. 7,323,578 results in a single liquid phase; Only the process conditions that require the addition of additional components to increase the selectivity to oxirane and to prolong the life of the catalyst are taught.

Literature references; Pandey et al., "Eco-friendly Synthesis of Epichlorohydrin Catalyzed by Titanium Silicalite (TS-2) Molecular Sieve and Hydrogen Peroxide," Catalysis Communications, 2007, 8, 379-382, using a solvent mixture of methanol and acetonitrile Reaction conditions for preparing oxides with TS-1 / H ₂ O ₂ are described. However, in the process described in this publication, the total amount of solvent used results in single phase reaction conditions.

Literature references; Zhang et al., "Effects of Organic Solvent Addition on the Epoxidation of Propene Catalyzed by TS-1," Reaction Kinetics and Catalysis Letters, 2007, 92 (1), 49-54], having methanol for the epoxidation of propylene. The use of solvent mixtures is discussed. Zhang et al., Thermogravimetric and pore volume analysis, replacing ˜24% of methanol in the system of Chang et al. With other solvents such as CCl ₄ , toluene or 1,2-dichloroethane. As measured by, it is described that the selectivity is increased and the catalyst pores are less clogged. Mixture of methanol and 1,2-dichloroethane (It provides 60% of the total composition of methanol) is sikimyeo suppress the decomposition of H ₂ O _2, while maintaining the H ₂ O ₂ conversion rate as compared with methanol alone, propylene glycol, and Inhibits the reaction of propylene oxide with propylene glycol mono-methyl ether. Although Chang et al. Describe using a mixture of solvents to increase the selectivity of the reaction, the total amount of solvent used results in single phase reaction conditions.

In summary, disadvantages of the known methods described in the prior art include:

(1) High levels of methanol are used in the reactor of the prior art process, whereby high levels of methanol must be separated from the product and recycled. This results in high energy usage for the process and high costs associated with it.

(2) The prior art method uses a primary separation step to recover and recycle the solvent and unreacted reactants. This requires the use of a high temperature at the bottom of the column, which requires the use of a high temperature throughout the column. All the water in the feed to the distillation column remained in contact with the product in the distillation column; Thus, the available water provides an opportunity to react with the product to form undesirable byproducts.

Prior art methods using solvent mixtures still use high levels of methanol and / or still use a single liquid phase.

Thus, there is a need to provide a method that does not have the problems of the prior art methods and that can operate at reaction conditions that solve all of the above problems and maintain high catalytic activity. Also, a process for producing propylene oxide using less total organic solvent (eg 230-500 g / kg) and much less methanol (eg less than 100 g / kg) than previously known methods It is desirable to provide. In addition, it is desirable to provide a method of increasing the selectivity of the reaction while extending the life of the catalyst without requiring any additional components to be removed in subsequent downstream processes.

Summary of the Invention

The present invention relates to an improved process for producing propylene oxide from propylene and hydrogen peroxide catalyzed by, for example, titanium silicalite-1 (TS-I) in a mixed solvent system.

One aspect of the invention relates to multiple liquid phase compositions, useful for preparing propylene oxide, wherein the composition comprises (a) propylene, (b) one or more peroxide compounds, (c) one or more A reaction mixture of a catalyst and (d) a solvent mixture, wherein the solvent mixture comprises (i) at least one alcohol or a combination of alcohols and (ii) at least one non-reactive cosolvent; The solvent is mixed at a predetermined concentration; The non-reactive cosolvent has a different boiling point than the propylene oxide; The propylene oxide may be partitioned into at least one of the solvents present in the solvent mixture during the reaction.

Another aspect of the invention relates to a process for preparing propylene oxide from propylene and peroxide compounds, wherein (a) propylene and (b) one or more peroxide compounds are used in the presence of (c) one or more catalysts and (d) Solvent mixture, wherein the solvent mixture comprises (i) at least one alcohol or combination of alcohols at a predetermined concentration and (ii) at least one non-reactive cosolvent at a predetermined concentration; the non-reactive cosolvent is different from the propylene oxide Having a boiling point; the propylene oxide may be dispersed in at least one of the solvents present in the solvent mixture during the reaction).

Still another aspect of the present invention

(a) reacting propylene, a catalyst, a peroxide compound, an alcohol or a mixture of alcohols and a non-reactive solvent together to form a reaction mixture, wherein the reactor mixture contents comprise two or more liquid phases and a catalyst; Simultaneously decanting the reactor mixture contents, wherein the liquid phase is separated from the catalyst and the liquid phase is recovered for further processing;

(b) separating the two liquid phases recovered from step (a) with each other to form an aqueous phase and an organic phase;

(c) in at least one separation unit operation, separating the organic compound present in the aqueous phase of step (b) from the aqueous phase to form an organic compound stream and a wastewater stream;

(d) recycling the organic compound stream of step (c) to the reaction mixture; Recovering the wastewater stream of step (c) or directing it to subsequent processing operations;

(e) recovering the organic phase of step (b) comprising, in one or more work units, an unreactive solvent, unreacted propylene and propylene oxide;

(f) separating propylene oxide from other components of the organic phase;

(g) recovering the propylene oxide product from step (f);

(h) recycling the unreacted propylene and non-reactive solvent streams of step (f) to the reaction mixture; And

(i) optionally purifying the recycle step of the process and / or purging all undesirable compounds that have accumulated in the recycle stream.

The present invention is advantageous because it specifies a multiphase solvent system in which the resulting propylene oxide is preferentially sequestered in the organic phase, reducing contact with water, thereby reducing by-products resulting from solvation of propylene oxide. . Both of these increase the selectivity of the reaction and extend the life of the catalyst. The multiphasic nature of the reaction mixture also allows subsequent recovery of propylene oxide by allowing simple separation of the aqueous and organic phases, for example by decantation, before recovering the useful product components that can be recycled from each stream. Promote

In addition, the present invention provides that the methanol concentration shown in the present invention is lower than the concentration shown in previously known methods, thereby reducing the loss of the oxirane groups of propylene oxide to solvolysis by methanol, thereby increasing the selectivity and This is advantageous because it maximizes the use of peroxides.

Although the reaction of the present invention is possible in the absence of methanol or solvent, it has been found that the catalyst life can be very short and can only be regenerated through firing. Although the present invention specifies a multiphase solvent system, the propylene oxide produced due to the presence of a small amount of methanol with a non-reactive cosolvent is preferentially sequestered in the organic phase, thereby reducing contact with water, thereby reducing propylene It is advantageous because it reduces by-products resulting from solvolysis of the oxirane group of oxides. Both of these increase the selectivity of the reaction and extend the life of the catalyst.

The following figures illustrate non-limiting aspects of the invention:
1 is a schematic flow diagram showing the overall flow into and out of the reaction / phase separation unit operation for one aspect of the method of the present invention.
FIG. 2 is a schematic flow diagram showing a reaction unit operation in which the reaction / phase separation is separated from the phase separation unit operation where the product and recycle stream separation section separates for one aspect of the process of the present invention.
FIG. 3 is a schematic flow diagram showing four block and reaction / phase separation unit operations of a unit operation for separating product from by-products and unreacted reactants after reaction / phase separation for one embodiment of the method of the present invention. .
4 is a schematic flow diagram of an aspect of the present invention showing two reactors in counter-current flows in series.

In a broad scope, the present invention relates to a process for the preparation of propylene oxide, wherein (a) propylene and (b) one or more peroxide compounds are added to (c) in the presence of one or more catalysts and (d) a solvent mixture, wherein The solvent mixture comprises reacting in the presence of (i) at least one alcohol at a predetermined concentration and (ii) at least one non-reactive cosolvent at a predetermined concentration).

Olefins useful in the process of the present invention include propylene; Preferred embodiments of the present invention include a process for epoxidizing propylene with propylene oxide using propylene aqueous hydrogen peroxide and a catalyst such as a titanium silicalite catalyst, TS-1.

The concentration of propylene is based on the total weight of the composition, referred to herein as the "total composition", including all components fed to the reactor to form the reaction mixture, including, for example, the sum of both the liquid component and the catalyst combined. Generally, about 1 wt% (wt%) to about 90 wt%, preferably about 4 wt% to about 50 wt%, more preferably about 4 wt% to about 30 wt%, most preferably about 4 wt% to about 20 wt% %to be. In one preferred embodiment of the invention, propylene is used at a concentration of about 8 wt% to about 20 wt%, based on the weight of the total composition.

In the broad term of the present invention, “peroxide compound” refers to any molecule containing one or more peroxide (—O—O—) functional groups, including organic or inorganic peroxides, peroxide adducts or peracids. These include, but are not limited to, for example, hydrogen peroxide, urea-hydrogen peroxide adducts, peracids and mixtures thereof.

One or more peroxides known from the prior art suitable for the reaction of propylene can be used in the present invention. Examples of peroxides may include tert-butyl hydroperoxide and ethylbenzene hydroperoxide. In the process of the invention, it is preferred to use hydrogen peroxide as the peroxide compound. Accordingly, the present invention provides a method of using hydrogen peroxide as a peroxide compound as described herein. Here, preference is given to using aqueous hydrogen peroxide.

The concentration of hydrogen peroxide is generally from about 1 wt% to about 35 wt%, preferably from about 1 wt% to about 20 wt%, more preferably from about 1 wt% to about 10 wt%, most preferably based on the weight of the total composition Is about 1 wt% to about 7 wt%.

In one preferred embodiment of the present invention, about 30 wt% aqueous hydrogen peroxide solution may be used such that the total amount of molecular hydrogen peroxide may be from about 1 wt% to about 7 wt%, based on the weight of the total composition.

The reaction process of the present invention where the reaction of propylene with hydroperoxide takes place under the pressure and temperature conditions set forth herein is preferably carried out in the presence of a suitable catalyst.

In the broad term of the present invention, "catalyst" may be a homogeneous or heterogeneous catalyst suitable for the epoxidation of propylene. Catalysts include, but may not be limited to, soluble metal catalysts such as ligand-bonded rhenium, tungsten and manganese, and solid silicate catalysts, preferably containing titanium, as well as heterogeneous forms thereof. Such solid catalysts may have a crystal structure of amorphous titanium on ZSM-5, MCM-22, MCM-41, beta-zeolite, or silica.

Preference is given to heterogeneous catalysts, in particular heterogeneous catalysts comprising porous oxide materials such as zeolites. In general, catalysts include, but may not be limited to, titanium-, vanadium-, chromium-, niobium-, or zirconium-containing zeolites as porous oxide materials.

Specific examples of suitable zeolites are pentasil zeolite structures, in particular X-ray-crystallographically BEA, MOR, TON, MTW, FER, MFI, MEL, CHA, ERI, RHO, GIS, BOG, NON, EMT, HEU, KFI , FAN, DDR, MTT, RUT, RTH, LTL, MAZ, GME, NES, OFF, SGT, EUO, MFS, MWW or mixed MFI / MEL structures and also titanium-, vanadium- with selected types ITQ-4 , Chromium-, niobium- and zirconium-containing zeolites. It is also possible to use titanium-containing zeolites having UTD-1, CIT-1 or CIT-5 structures in the process of the invention. Additional titanium-containing zeolites that may be mentioned are those having a ZSM-48 or ZSM-12 structure. Particular preference is given to using Ti zeolites having MFI, MEL or mixed MFI / MEL structures in the process of the invention. In addition, Ti-containing zeolite catalysts, generally designated as "TS-1", "TS-2" and "TS-3", and also Ti zeolites having a framework structure homogeneous with the MWW-zeolite are particularly preferred.

Particular preference is given to using heterogeneous catalysts comprising titanium-containing silicalite TS-1 in the process of the invention.

In the process of the invention it is possible to use the porous oxide material itself as a catalyst. However, it is of course also possible to use shaped bodies comprising porous oxide materials as catalysts. Molded bodies from porous oxide materials can be prepared using methods well known in the art.

The concentration of the catalyst is generally from about 0.1 wt% to about 30 wt%, preferably from about 0.1 wt% to about 20 wt%, more preferably from about 0.1 wt% to about 10 wt%, based on the weight of the total composition, Most preferably about 0.5 wt% to about 5 wt%.

In a preferred embodiment of the present invention, propylene is converted to propylene oxide using a catalyst such as titanium silicalite (TS-1) having an MFI structure and hydrogen peroxide. In this embodiment, the concentration of catalyst is most preferably from about 0.5 wt% to about 3 wt%, based on the weight of the total composition.

The reaction is carried out in the presence of two liquids, generally an organic phase and an aqueous phase, but the catalyst is typically present in solid form in the reaction mixture. By "two phases" is meant at least two liquid phases. The solid form of the catalyst may be a powder for a slurry type reactor or an extrudate for a fixed bed reactor. In one embodiment of the invention for a slurry reactor system, the catalyst can be mixed with the organic phase and then the aqueous phase can be added to the mixture to prevent degradation of the peroxide. For slurry reactor systems, for example, the size of the catalyst can be less than about 100 μm. The amount of individual components for this embodiment should be selected based on their physical properties such that when mixed together the liquid composition comprises at least two phases, organic and inorganic phases.

Component (d) of the present invention is a solvent mixture; Wherein the solvent mixture comprises (i) at least one alcohol or a combination of two or more alcohols at a predetermined concentration and (ii) at least one non-reactive cosolvent at a predetermined concentration in addition to the solvent component (i); Here, the non-reactive cosolvent has a different boiling point than the propylene oxide. The solvent mixture is selected to include one or more solvents having the property of causing propylene oxide to be distributed to the one or more solvents present in the solvent mixture during the reaction. One or more solvents are said to have a high affinity for propylene oxide.

“Partition” herein refers to the tendency for propylene oxide to be more soluble in the solvent mixture than in other phases or phases present in the reaction mixture in the reactor. This is quantified by the ratio of propylene oxide concentration on the solvent mixture to the total amount of propylene oxide in the reaction mixture. In general, the solvent is chosen such that at least 90% of the propylene oxide in the reaction mixture remains on the solvent. Preferably, at least 99% of the propylene oxide remains on the solvent. Most preferably, at least 99.9% of propylene oxide remains on the solvent.

In the general scope of the invention, any alcohol or a mixture of two or more alcohols may be used as the first solvent component of the solvent mixture. Alcohols include, for example, lower alcohols such as alcohols having less than 6 carbon atoms, such as methanol, ethanol, propanol (e.g. isopropanol), butanol (e.g. tert-butanol) and pentanol and two or more of these alcohols. Combinations; Halogenated alcohols; And mixtures thereof. Preference is given to using C1-C4 alcohols (or mixtures thereof), and more particularly to using methanol as the alcohol for the first solvent component. In particular, methanol acts not only as a solvent but also as an activator for the catalyst.

The concentration of alcohol (s) is generally from about 3 wt% to about 40 wt%, preferably from about 3 wt% to about 20 wt%, more preferably from about 3 wt% to about 10 wt%, based on the weight of the total composition, Most preferably about 3 wt% to about 7 wt%. In a preferred embodiment of the invention, methanol may be used at a concentration of about 3 wt% to about 7 wt%, based on the weight of the total composition.

In the broad term of the present invention, "non-reacting or nonreactive co-solvent" is defined as any reagent that is inert to the reaction, ie the solvent does not participate in the reaction under the reaction conditions, It does not react significantly with the peroxide compound or product under conditions, can be dissolved in water to a minimum, and has a boiling point significantly different from propylene oxide. Criteria for non-reactive cosolvents that must be "non-reactive" for use in the present invention include, for example, certain olefins, carboxylates, ethers, esters, acyl halides, aldehydes, carbonates, activated aromatics, thiols, amines, Molecules containing nitro-functional groups, and certain ketones that are reactive with peroxides, such as acetone and methyl ethyl ketone, can be excluded.

Still, cosolvents useful in the present invention, in particular, include water; Aliphatic, cycloaliphatic and aromatic hydrocarbons; Esters such as methyl acetate or butyrolactone; Ethers such as diethyl ether, tetrahydrofuran, dioxane, 1,2-diethoxyethane and 2-methoxyethanol; Amides such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone; Sulfoxide; Specific ketones; Dioxes or polyols, preferably those having less than 6 carbon atoms; And alcohols other than or different from the first solvent component (d) (i) above. In addition, one or more suitable solvents usable in the present invention include solvents containing C ₃ -C ₁₈ straight and cyclic alkanes, halogenated hydrocarbons, inactivated aromatics and nitriles such as acetonitrile; Or mixtures thereof. For example, the cosolvent may be carbon tetrachloride, propyl chloride, chloroform, dichloromethane, dichloroethane, hexane, octane, decalin, perfluorodecalin, mono- or poly-chlorinated benzene, mono- or poly-brominated benzene, acetophenone, benzo Nitrile, acetonitrile, trichlorotrifluoroethane, trichloroethanol, trifluoroethanol, tricresyl phosphate or mixtures of two or more of the foregoing compounds, but may not be limited thereto.

In a particularly advantageous aspect of the invention, the non-reactive cosolvents can be selected from those having similar solubility parameters as propylene oxide, as estimated using Hansen parameters and Teas plots.

The concentration of the cosolvent is generally from about 5 wt% to about 80 wt%, preferably from about 5 wt% to about 70 wt%, more preferably from about 40 wt% to about 70 wt%, based on the weight of the total composition Preferably from about 50 wt% to about 70 wt%.

In a preferred embodiment of the invention, 1,2-dichlorobenzene can be advantageously used as a non-reactive cosolvent at a concentration of about 55 wt% to about 65 wt%, based on the weight of the total composition.

Other optional ingredients that may be useful in the present invention are those components commonly used in formulations known to those skilled in the art. For example, optional components can include compounds that can be added to the composition to enhance the reaction rate, selectivity of the reaction, and / or catalyst life. Preferred optional components useful in the compositions of the present invention and their relative concentrations can be determined by the skilled person.

As an illustration of one preferred embodiment of the process according to the invention, propylene oxide is prepared from propylene and hydrogen peroxide in at least one reaction step in the presence of a mixture of two or more solvents, wherein one of the solvents is methanol. One embodiment of the present invention comprises from about 8 wt% to 20 wt% of a small amount (eg, 3 wt%-7 wt%) of methanol with an unreactive cosolvent and an excess, eg, based on the weight of the total composition. It may be directed to a specific mixture with propylene. The resulting reaction mixture consists of two or more liquid phases, a solid catalyst, and a vapor phase in contact with other phases and components present in the reaction mixture, which increases the selectivity of the reaction without requiring other additives.

The reaction of propylene with hydrogen peroxide to produce propylene oxide can be carried out herein by any suitable method, for example in a batch process or continuously. In one embodiment, the process can be carried out in one or more batch reactors or one or more continuous reactors or combinations thereof.

With regard to the continuous process, any suitable reactor arrangement may be useful in the present invention. Thus, for example, propylene oxide can be prepared in a cascade of two or more reactors connected in series with each other. Contemplated processes useful in the present invention also include, for example, reactors arranged in parallel. Combinations of these processes are also possible. If two or more reactors are connected in series, suitable intermediate treatments may also be provided between the reactors.

For example, in a first aspect of the process according to the invention, propylene, peroxide, alcohol (s), one or more solvents and catalyst are fed to one or more reactors and the resulting liquid phase is removed from the reactor; The catalyst phase in the reactor is separated from the liquid portion of the effluent before separating the liquid phase. This can be done in a batch process or continuously. In this first embodiment, any portion of the reactor effluent may be recycled to the reactor as feed.

In a second aspect of the process according to the invention, propylene, peroxide, alcohol (s), one or more solvents and catalyst are fed to one or more reactors, both the resulting liquid phase and catalyst are removed from the reactor and in subsequent operations Isolate further. This can be done in a batch process or continuously. In this second embodiment, any portion of the reactor effluent may be recycled to the reactor as feed.

In a third aspect of the process according to the invention, two or more reactors are connected in series. Propylene, peroxide, alcohol (s), one or more solvents are fed to a first reactor containing a catalyst and the liquid phase is removed from the reactor; The catalyst phase in each reactor is separated from the liquid portion of the effluent before separating the liquid phase. In this third aspect, all or a portion of the liquid effluent from the first reactor and subsequent reactor (s) may be fed to subsequent reactors or reactors containing the catalyst, further comprising fresh propylene, peroxide, alcohol (s) ), One or more solvents and catalyst feed may optionally be added to each subsequent reactor along with some of the effluent from any previous reactor.

In a fourth aspect of the process according to the invention, two or more reactors are connected in series. Propylene, peroxide, alcohol (s) and one or more solvents are fed to the first reactor containing the catalyst and the resulting liquid phase and catalyst are removed from the first reactor. The catalyst and liquid phases are separated in subsequent work. In this fourth aspect, all or part of the liquid effluent and optionally some of the catalyst from the first reactor and subsequent reactor (s) can be fed to subsequent reactors or reactors containing the catalyst, further comprising fresh propylene, Peroxide, alcohol (s), one or more solvents and catalyst feed may optionally be added to each subsequent reactor along with some of the effluent from any previous reactor.

In a fifth aspect of the process according to the invention, two or more reactors operate in parallel. Propylene, peroxide, alcohol (s) and one or more solvents are fed to each reactor containing a catalyst and the resulting liquid phase is removed from each reactor. In this aspect of the invention, the catalyst phase in each reactor is separated from the liquid portion of the effluent before separating the liquid phase. In this fifth aspect of the invention, a portion of the effluent stream from the reactor can be recycled back to the same reactor with fresh feed. The reactor effluent may be separated or combined for further processing.

In a sixth aspect of the process according to the invention, one or more reactors operate in parallel. Propylene, peroxide, alcohol (s) and one or more solvents are fed to each reactor containing a catalyst and the resulting liquid phase and catalyst are removed from each reactor. In this embodiment, a portion of the liquid effluent and optionally a portion of the catalyst from each reactor can be recycled back to the same reactor with fresh feed. In this sixth aspect, the reactor effluent may be separated or combined for further processing.

In a seventh aspect of the process according to the invention, two or more reactors are connected in series and propylene and peroxide are fed countercurrently through the reactor. At least a portion of the alcohol (s), or at least a portion of the alcohol (s), one or more solvents and a catalyst, are fed to the first reactor containing the catalyst, and without peroxide and alcohol (s) or at least a portion of the alcohol (s) Is fed to the second reactor containing the catalyst or, in the case of two or more reactors, to the final reactor. Both the effluent of the final reactor and the aqueous phase of any reactor downstream of the first reactor, containing the partially converted peroxide, are the catalyst phase and the organic phase containing the oxirane, one or more solvents and any residual propylene. From the feed and feed to one or more upstream reactors in series. The organic phase of the effluent from the first and subsequent reactor (s) containing unreacted propylene, alcohol (s), one or more solvents and oxirane is separated from both the catalyst phase and the aqueous phase of the effluent and the catalyst It is fed to one or more downstream reactors in-line. This flow pattern is repeated for all reactors in tandem. In this seventh aspect of the invention, the catalyst phase in each reactor is separated from the liquid portion of the effluent before separating the liquid phase.

In an eighth aspect of the process according to the invention, two or more reactors are connected in series and propylene and peroxide are fed countercurrently through the reactor. Propylene, all or part of the alcohol (s), one or more solvents and catalysts are fed to the first reactor containing the catalyst and all or part of the peroxide and alcohol (s) are supplied to the second reactor, or two or more reactors In the case of feed to the final reactor. Separation of both the effluent of the final reactor and the aqueous phase downstream of the reactor of the first reactor containing the partially converted peroxide from the catalyst phase and the organic phase containing oxirane, one or more solvents and any residual propylene And one or more upstream reactors in-line containing the catalyst. The organic phase of the effluent from the first and subsequent reactor (s) containing unreacted propylene, alcohol (s), one or more solvents and oxirane is separated from both the catalyst phase and the aqueous phase of the effluent and the catalyst It is fed to one or more downstream reactors in-line. This flow pattern is repeated for all reactors in tandem. In this eighth aspect of the invention, the catalyst phase in each reactor is separated from the liquid portion of the effluent in one or more separate operation (s).

In a ninth aspect of the process according to the invention, two or more reactors are connected in series and propylene and peroxides are fed through the reactor in cross-current flow. The catalyst, the first portion of propylene, the portion of the alcohol (s), one or more solvents and all of the peroxides are all introduced into the first reactor containing the catalyst and therein to form a first portion of oxirane. One part epoxidation is carried out. The liquid phase of the effluent of this reactor and subsequent reactor (s) is first separated from the catalyst and the organic phase of the first reactor containing unreacted propylene, alcohol (s), one or more solvents and the resulting oxirane It is fed to one or more subsequent reactors containing it, to which fresh peroxide feed is introduced. This flow pattern is repeated for all reactors in tandem. The catalyst is separated from the final reactor effluent before separating the two liquid phases.

In a tenth aspect of the process according to the invention, two or more reactors are connected in series and propylene and peroxides are fed crosswise through the reactor. A first portion of propylene, a portion of the alcohol (s), one or more solvents and peroxides all are introduced into a first reactor containing a catalyst and a first portion of propylene therein to form a first portion of oxirane Epoxidation is carried out. The liquid phase of the effluent of this reactor is discharged with the catalyst and the catalyst is separated from the liquid phase in subsequent operations. The organic phase of the first reactor and subsequent reactor (s) containing unreacted propylene, alcohol (s), one or more solvents and the resulting oxirane is fed to one or more subsequent reactors containing the catalyst and thus fresh peroxide Feed and catalyst are introduced. This flow pattern is repeated for all reactor (s) in tandem. The catalyst is separated from the final reactor effluent liquid phase in subsequent operations.

In an eleventh aspect of the process according to the invention, two or more reactors are connected in series and propylene and peroxide are fed crosswise through the reactor. A first portion of propylene, a portion of the alcohol (s), one or more solvents and peroxides all are introduced into a first reactor containing a catalyst and a first portion of propylene therein to form a first portion of oxirane Epoxidation is carried out. The liquid phase of the effluent of this reactor is first separated from the catalyst and the aqueous phases of the first and subsequent reactor (s) containing the unreacted peroxide are fed to one or more subsequent reactors containing the catalyst, thereby providing fresh olefins, Alcohol (s), one or more solvents and a catalyst are introduced. This flow pattern is repeated for all reactors in tandem. The catalyst is separated from the final reactor effluent before separating the two liquid phases.

In a twelfth aspect of the process according to the invention, two or more reactors are connected in series and propylene and peroxide are fed crosswise through the reactor. A first portion of propylene, a portion of the alcohol (s), one or more solvents and peroxides all are introduced into a first reactor containing a catalyst and a first portion of propylene therein to form a first portion of oxirane Epoxidation is carried out. The liquid phase of the effluent of this reactor is discharged with the catalyst and the catalyst is separated from the liquid phase in subsequent operations. The aqueous phases of the first and subsequent reactor (s) containing unreacted peroxide are fed to one or more subsequent reactors containing catalyst, to which fresh propylene, alcohol (s), one or more solvents and catalyst are introduced. The catalyst is separated from the final reactor effluent liquid phase in subsequent operations.

The temperature and pressure of the reaction medium can be altered both or independently during the production of propylene oxide from propylene and hydrogen peroxide during the process.

With regard to physical parameters such as temperature or pressure, there are no special restrictions. The process of the present invention can carry out the reaction at a temperature effective to achieve the desired reaction. The temperature of the reaction generally ranges from about 10 ° C. to about 100 ° C .; More preferably about 20 ° C. to about 80 ° C .; Most preferably from about 40 ° C to about 65 ° C. Other conditions for carrying out the process of the invention, such as pressure, will be relative pressures and other conditions of the reaction associated with the reactor composition at a particular temperature. However, the reaction is preferably carried out at a pressure in the range of 1 bar to 30 bar, preferably 8 bar to 20 bar, particularly preferably 8 bar to 15 bar.

In one embodiment, the process of the present invention produces a waste stream that does not have a significant amount of sodium chloride (NaCl). By "without an equivalent" in connection with sodium chloride is meant herein generally less than about 1 wt%, preferably less than about 0.5 wt% and most preferably less than about 0.1% by weight of the total composition. do.

In another embodiment of the process of the invention, the two liquid phases formed during the reaction in the reaction mixture are separated from each other and from the catalyst. Each liquid phase is then separated into smaller components for recycle, product recovery or purge stream separation. Unreacted propylene, alcohol (s) and one or more nonreactive solvents are returned to the reaction section. Water and byproducts are purged from the process.

In yet another embodiment, the methods of the present invention can include immediate separation of water from the reaction product to minimize contact of such compounds in the hot compartment of the separation compartment to minimize byproduct formation.

In another embodiment, the reaction environment can include a vapor phase in contact with the multi-liquid phase composition. After the reaction, the organic phase and the aqueous phase are separated from the catalyst and from each other. Returning unreacted propylene, alcohol (s) and one or more nonreactive solvents to the reaction mixture; Water and byproducts are purged from the process.

In a particularly preferred embodiment, the present invention

(a) in at least one reaction step, reacting a solvent mixture comprising propylene, a catalyst, a peroxide compound, at least one alcohol and at least one non-reactive solvent to form a reaction mixture, wherein the reaction mixture contents are at least two liquids Phase and a catalyst); Simultaneously decanting the contents of the reaction mixture, wherein the liquid phase is separated from the catalyst and the liquid phase is recovered for further processing;

(b) separating the two liquid phases formed in step (a) from each other to form an aqueous phase and an organic phase;

(c) in at least one separation unit operation, separating the organic compound present in the aqueous phase of step (b) from the aqueous phase to form an organic compound stream and a wastewater stream;

(d) recycling the organic compound stream of step (c) to the reaction mixture; Recovering the wastewater stream of step (c) or directing it to subsequent processing operations;

(e) recovering the organic phase of step (b) comprising, in one or more work units, an unreactive solvent, unreacted propylene and propylene oxide;

(f) separating propylene oxide from other components of the organic phase;

(g) recovering the propylene oxide product from step (f);

(h) recycling the unreacted propylene and non-reactive solvent streams of step (f) to the reaction mixture; And

(i) optionally purging undesired compounds accumulated in the recycle stream.

Step (a) of the method may be referred to as a "reaction / gradient filtration step".

In the process of the invention, the reaction of propylene with hydrogen peroxide takes place in a reactor suitable for this purpose. Preferred starting materials used in the reaction are propylene, hydrogen peroxide and methanol. In this way, the starting material can be fed to the reactor in one or more streams. The stream is fed to the reactor in liquid form to form a multiphase or at least two phase system. In the process of the invention, it is preferred to feed the reactor a stream consisting of a combination of aqueous starting materials and a stream consisting of a combination of organic starting materials.

Any contemplated reactor known in the art suitable for carrying out each reaction may be used. In the present invention, the term "reactor" or "reaction vessel" is not limited to a single vessel. Rather, it is also possible to use a cascade of stirred vessels as the reactor as described above.

The reaction vessel may be, for example, one or more continuous stirred tank reactors (CSTRs) or tubular reactors; Or any well known suitable type, including combinations thereof. The reaction vessel may also be a batch reactor. The reactor may include any other well known liquid-liquid contactor, such as, for example, Karr Column. In the case of the reaction step, sufficient mixing may be necessary to ensure that propylene, hydrogen peroxide and catalyst are in intimate contact. Mixing is the same as, for example, stirring using an agitator, adjusting the droplet size in a countercurrent extruder, inducing shear force into the mixing element in a tubular reactor or loop reactor, or other means. It may include any known mixing means not limited thereto. The mixing strength is preferably from 1 to 100 hp / 1000 gal, more preferably from 1 to 10 hp / 1000 gal, and most preferably from 2 to 4 hp /, in the power / volume input to the reactor. It should be 1000 gal. The interfacial area needs to be high enough so that sufficient mass transfer occurs for the reaction to occur.

Once the catalyst is separated from the liquid reaction phase, the multiple reaction phase is followed by subsequent propylene oxide by simple separation of the aqueous phase and the organic phase, for example by decantation, before recovery of the recyclable useful product component from each stream. Promote recovery (see, eg, FIGS. 1-4). By reducing the amount of methanol to some level lower than that used in the prior art methods, the selectivity of the reaction to propylene oxide can be increased because the reaction of methanol with propylene oxide is reduced. When methanol is reduced, a reaction mixture of two or more liquid phases results, which is the majority of propylene oxide remaining in the organic phase, which is a by-product formed from the reaction of propylene oxide with water, for example propanediol and methoxy It is advantageous because it reduces the propanol. In addition, many of the heavy by-products formed remain in the aqueous phase. It is an important element of the reaction that the reaction remains in two or more liquid phases, so that the formed propylene oxide is separated from the aqueous phase and sequestered into one of the organic phases. This greatly reduces the hydrolysis of propylene oxide into byproducts.

The reaction can be carried out in a mixed solvent system consisting of a small amount of methanol and an unreactive cosolvent. The advantages provided by the system of the present invention are increased catalyst life and reduced energy costs for separation. For example, based on the simulation of the method taught in US Pat. No. 7,138,534, the embodiment presented as FIG. 3 reduces the energy required per pound of propylene oxide produced by at least 50%. Based on the weight of the total composition, it is generally from about 3% to about 40%, preferably from about 3% to about 20%, more preferably from about 3% to about 10%, most preferably from about 3% The presence of methanol in the reactor at a concentration of about 7% prolongs catalyst life as described in the examples.

Another advantage of the present invention is that the addition of non-reactive cosolvents increases catalyst life by reducing plugging of catalyst pores.

Still another advantage of the present invention is that due to the biphasic nature of the reaction mixture, the organic phase and the aqueous phase can be separated by decantation, reducing the size and steam consumption of the distillation column compared to methods using high levels of methanol. It can be done.

It has been found that TS-1 activity in epoxidation of propylene with H ₂ O ₂ can be maintained by using a mixture of solvents containing less than 10% methanol with non-reactive cosolvents.

The invention will now be described with reference to the non-limiting embodiments shown in FIGS. 1-4, which illustrate the method of the present invention, the same reference numerals are used to refer to the same parts throughout the several views. In the following description, the term “vessel” is defined herein to mean one or more portions of the device. "Reaction / gradient vessel" is defined herein to mean all of the embodiments already described above.

1 shows a process of the invention, generally represented by numeral 100, including, for example, a reaction / gradient filtration vessel 10, wherein the propylene reactant feed stream 11 is a reaction / gradient filtration vessel. May be introduced in (10). 1 shows the reaction / tilt filtering step in the first, third, fifth, seventh, ninth and eleventh embodiments described above. The reaction / gradient vessel 10 may comprise, for example, one or more continuous stirred tank reactors (CSTRs) or tubular reactors as described above; Or any well known suitable type, including combinations thereof. The reaction vessel 10 may also include a batch reactor.

Hydroperoxide feed stream 12, such as hydrogen peroxide; Single or mixed alcohol feed stream 13 containing a minimum amount of alcohol such as methanol; And, for example, an inert solvent feed stream 14 comprising ortho dichlorobenzene is also introduced into the vessel 10. The reaction / tilt vessel 10 contains a solid catalyst, for example titanium silicalite, such as TS-1, which is within the boundaries of the apparatus as shown in FIG. Streams 11, 12, 13 and 14 can be introduced into the vessel 10 separately or together. Also, optionally, all of the streams 11, 12, 13 and 14 can be combined together into one feed stream. Stream 11, 12, 13 or 14 may be introduced at a single point or multiple points of vessel 10. The relative amounts of the streams 11, 12, 13 and 14 are such that when combined in the vessel 10 a separate aqueous phase is present with at least one organic phase, a solid catalyst phase and optionally with the reaction liquid and a vapor phase over the catalyst. Is selected.

In vessel 10, propylene may be partially or fully converted to the reaction product of propylene oxide plus propylene oxide with methanol with a TS-1 catalyst. For example, stream 16 containing predominantly water, unreacted hydrogen peroxide, propanediol, methoxypropanol and mixed alcohols can be removed from vessel 10; It may be sent to a reservoir, to another operation for further processing such as purification, or to another device for further reaction or processing. For example, stream 17 containing predominantly unreacted propylene, propylene oxide, single or mixed alcohols and non-reactive solvents such as ortho dichlorobenzene can be removed from vessel 10; It may be sent to a reservoir, to another operation for further processing such as purification, or to another device for further reaction or processing.

2 shows another embodiment of the process of the present invention, generally represented by the number 200, wherein propylene feed stream 21 may be introduced into reaction vessel 20. FIG. 2 shows the reaction / tilt filtering steps in the second, fourth, sixth, eighth, tenth and twelfth embodiments described above. The reaction vessel 20 may comprise, for example, one or more continuous stirred tank reactors (CSTRs) or tubular reactors as described above; Or any well known suitable type, including combinations thereof. It may also be a batch reactor. Hydroperoxide feed stream 22, such as hydrogen peroxide; Single or mixed alcohol feed stream 23 containing a minimum amount of alcohol such as methanol; And, for example, an inert solvent feed stream 24, including ortho dichlorobenzene, is also supplied to the vessel 20. The reaction vessel 20 contains a solid catalyst 25, for example titanium silicalite, such as TS-1.

Streams 21, 22, 23, and 24 may be introduced to vessel 20 separately or together. Also, optionally, all of the streams 21, 22, 23 and 24 can be combined together into one feed stream. Any of the streams 21, 22, 23 or 24 can be introduced at a single point or multiple points of the vessel 20. The relative amounts of the streams 21, 22, 23 and 24 are such that when combined in the vessel 20 a separate aqueous phase is present with at least one organic phase, solid catalyst phase and optionally with the reaction liquid and vapor phase over the catalyst. Is selected.

Recirculation stream 33 comprising predominantly solid catalyst, TS-1, may also be supplied to vessel 20. Optionally, solid catalyst may remain in vessel 20, in which case stream 33 does not flow.

In the embodiment of the present invention shown in FIG. 2, the mixed contents of the vessel 20 containing all the liquid phase and optionally the solid catalyst can be supplied to the vessel 30 as stream 26. Vessel 30 may include any well known suitable separation vessel, including gradient filtration, hydrocyclones, mechanically driven high specific gravity devices, or any suitable known separation apparatus known in the art. For example, stream 31 consisting primarily of water, unreacted hydrogen peroxide, propanediol, methoxypropanol and a single or mixed alcohol may be removed from vessel 30; It may be sent to a reservoir, for further processing such as purification, or to other devices for further reaction. For example, stream 32 containing predominantly unreacted propylene, propylene oxide, single or mixed alcohols and non-reactive solvents such as ortho dichlorobenzene can be removed from vessel 30 and sent to the reservoir or It can be sent to another operation for further processing, such as purification, or to other devices for further reaction or processing.

3 shows another embodiment of the process of the present invention, generally indicated by the numeral 300, wherein a propylene feed stream 11 may be introduced into the reaction / incline filtration vessel 10. The reaction / tilt vessel 10 may, for example, comprise one or more continuous stirred tank reactors (CSTRs) or tubular reactors; Or any well known suitable container type, including combinations thereof. Vessel 10 may also be a batch reactor. The liquid phase and the catalyst may be separated by any well known separation means such as, for example, gradient filtration, hydrocyclones, mechanically driven high specific gravity devices, any suitable known separation device or combinations thereof. .

Hydroperoxide feed stream 12, such as hydrogen peroxide; Single or mixed alcohol feed stream 13 containing a minimum amount of alcohol such as methanol; And, for example, an inert solvent feed stream 14 comprising ortho dichlorobenzene is also introduced into the vessel 10. The reaction / tilt vessel 10 contains a solid catalyst, for example titanium silicalite, such as TS-1, which is within the boundaries of the apparatus as shown in FIG. 3 as the vessel 10. Streams 11, 12, 13 and 14 can be introduced into the vessel 10 separately or together. Also, optionally, all of the streams 11, 12, 13 and 14 can be combined together into one feed stream. Any of the streams 11, 12, 13 or 14 can be introduced at a single point or multiple points of the vessel 10. The relative amounts of the streams 11, 12, 13 and 14 are such that when combined in the vessel 10 a separate aqueous phase is present with at least one organic phase, a solid catalyst phase and optionally with the reaction liquid and a vapor phase over the catalyst. Is selected.

In vessel 10, propylene may be partially or fully converted to propanediol from the reaction product of propylene oxide plus propylene oxide with methanol with a TS-1 catalyst and from the hydrolysis of propylene oxide. For example, stream 16 containing predominantly water, unreacted hydrogen peroxide, propanediol, methoxypropanol and a single or mixed alcohol may be removed from vessel 10 and sent to vessel 40. The vessel 40 produces, for example, a stream 42 consisting primarily of water, propanediol, methoxypropanol and a stream 41 consisting mainly of light feed impurities or by-products, for example. Both stream 41 and stream 42 are purged from the process. The stream from vessel 40 can be sent to vessel 60 as stream 43 for further recovery of unreacted propylene, single or mixed alcohol and propylene oxide.

For example, stream 17 containing predominantly unreacted propylene, propylene oxide, single or mixed alcohols and non-reactive solvents such as ortho dichlorobenzene can be removed from vessel 10 and vessel 50 Can be sent to. Vessel 40 may comprise, for example, a distillation column or a combination of two or more distillation columns.

In vessel 50, a non-reactive solvent, such as ortho dichlorobenzene, may be separated and exit vessel 50 as stream 54. Optionally, a portion of stream 54 may be purged from the process as stream 55. Stream 56 as a net net of stream 54 less than any material removed as stream 55 may be recycled to vessel 10. For example, stream 51, which mainly comprises unreacted propylene, mixed alcohol and propylene oxide, exits vessel 50. Optionally, a portion of stream 51 may be removed and purged from the process as stream 53. Stream 52 as a net amount of stream 51 less than any material removed as stream 53 may be supplied to vessel 60. The vessel 50 may comprise, for example, a distillation column or a combination of two or more distillation columns.

In vessel 60, unreacted propylene can be separated and removed from vessel 60 as stream 62. Optionally, a portion of stream 62 may be purged from the process as stream 63. The net amount of stream 62 less than any material removed as stream 63 may be recycled back to vessel 10 as stream 64. For example, stream 61 comprising propylene oxide and a higher boiling compound than propylene oxide may be supplied to vessel 70. Vessel 60 may, for example, comprise a distillation column or a combination of two or more distillation columns.

In the vessel 70, the product propylene oxide can be separated off and produced as stream 71. The lower boiling compound than propylene oxide is discharged from vessel 70 as stream 73. The higher boiling compound than propylene oxide is discharged from vessel 70 as stream 72. Optionally, a portion of stream 72 may be purged from the process as stream 74. A net amount of stream 72 less than any material removed as stream 74 may be recycled back to vessel 10 as stream 75. Vessel 70 may include, for example, a distillation column or a combination of two or more distillation columns.

4 shows another embodiment of the method of the present invention, generally represented by numeral 400, comprising two reactors, vessels 410 and 411, connected in series as described above in connection with the seventh embodiment. . The feed is introduced into vessel 410 as propylene feed stream 411, single or mixed alcohol stream 413 and inert solvent feed stream 414. Streams 411, 413, and 414 may be introduced to vessel 410 separately or together. Also, optionally, all of the streams 411, 413, and 414 can be combined together into one feed stream. Any of the streams 411, 413 or 414 can be introduced at a single point or multiple points of the vessel 410. The feed is introduced to vessel 420 as peroxide feed stream 412 and as a single or mixed alcohol stream 478. Streams 412 and 478 can be introduced to vessel 420 separately or together. Further, optionally, both streams 412 and 478 can be combined together into one feed stream. Either streams 412 and 478 can be introduced at a single point or multiple points of the vessel 420.

An aqueous effluent from vessel 420 as stream 417 is supplied to vessel 410. Organic effluent from vessel 410 as stream 416 is supplied to vessel 420. Organic phase effluent from vessel 420 leaves the in-line reactor as stream 419. The aqueous phase effluent from vessel 410 leaves the tandem reactor as stream 415.

Propylene oxide produced by the process of the invention can be used in a variety of applications, including, for example, the production of polyether polyols for the production of polyurethane plastics or the production of propylene glycol.

Example

The following examples further illustrate the invention in detail, but should not be construed as limiting the scope of the invention.

The following standard analysis apparatus and methods are used in the examples:

Gas chromatography was performed on an HP 6890 series G1530A GC with an HP 7682 series injector and FID detector. An HP-1701 14% cyanopropyl phenyl methyl column having a length of 60.0 m, a diameter of 320.00 μm and a thickness of 1.00 μm was used at a temperature of 35 to 250 ° C.

Peroxide amounts were analyzed by iodine titration with 0.01 N sodium thiosulfate. The peroxide concentration can be calculated as follows: ppm H ₂ O ₂ = (mL of titrant used) (0.01 N) (17000) / g of sample. Titration was performed using a Mettler Toledo DL5x V2.3 titrator with DM140 sensor.

Example  One

Propylene (100 g), TS-1 catalyst (10 g), methanol (25 g) and o-dichlorobenzene (295 g) were charged with N ₂ purge and reflux condenser with stainless steel cooling coil, thermocouple, mechanical stirrer, addition funnel, gas scrubber / It is added to a 750-mL jacketed reactor with a cold finger combination. About 35 wt% / aqueous hydrogen peroxide (70 g) was charged to the addition funnel and then slowly added to the reactor after the propylene / catalyst / methanol mixture had reached 25.5 ° C. The mixture is stirred at 600 rpm and the exothermic reaction raises the temperature of the mixture to 40 ° C., where the temperature is maintained using a cooling coil.

Samples are taken from the reactor and then analyzed by gas chromatography (GC). If propylene oxide is analyzed via GC and the reaction is deemed complete (after 60 minutes), both phases are analyzed by GC and the amount of peroxide remaining is determined by titration with sodium thiosulfate. The results of this experiment are as follows:

Conversion of hydrogen peroxide: 99%.

Selectivity (part of reacted H ₂ O _{2 to} produce propylene oxide): 95%.

Yield (propylene oxide prepared to total propylene, resulting when all H ₂ O ₂ is made of propylene oxide): 94%.

[H ₂ O ₂ conversion rate * selectivity for PO = 99/100 * 94/99 = 94% yield for PO].

Claims (19)

A multiple liquid phase composition, useful for preparing propylene oxide, wherein the composition comprises a reactive mixture of (a) propylene, (b) peroxide compound, (c) one or more catalysts, and (d) a solvent mixture. Wherein the solvent mixture comprises a mixture of two or more solvents comprising (i) at least one alcohol and (ii) at least one non-reactive cosolvent other than the at least one alcohol; The at least one alcohol and the at least one non-reactive cosolvent are mixed at a predetermined concentration; The at least one cosolvent has a different boiling point than the propylene oxide; The propylene oxide may be partitioned into at least one of the solvents present in the solvent mixture during the reaction. The composition of claim 1, wherein the concentration of propylene constitutes about 10% to about 90% by weight. The composition of claim 1, wherein the concentration of the peroxide compound constitutes about 1% to about 35% by weight. The composition of claim 1, wherein the at least one catalyst comprises a titanium silicate catalyst. The composition of claim 1, wherein the concentration of the one or more catalysts comprises about 0.1% to about 10% by weight. The composition of claim 1, wherein the one or more alcohols in the solvent mixture comprise C1 to C4 alcohols. The composition of claim 6, wherein the concentration of the one or more alcohols comprises about 3% to about 40% by weight. The composition of claim 1, wherein the at least one alcohol in the solvent mixture comprises methanol. The composition of claim 8, wherein the concentration of methanol comprises less than about 10% by weight. The compound of claim 1, wherein the one or more non-reactive cosolvents are C ₃ -C ₁₈ straight and cyclic alkanes; Halogenated hydrocarbons; Inactivated aromatics; amides; Solvents containing nitrile; Alcohols different from the alcohol solvents; Or a mixture thereof. The composition of claim 1, wherein the concentration of the one or more non-reactive cosolvents comprises about 5% to about 70% by weight. A process for the preparation of propylene oxide from propylene and peroxide compounds, wherein (a) propylene and (b) peroxide compounds are added to (c) in the presence of at least one catalyst and (d) a solvent mixture, wherein the solvent mixture is (i At least one alcohol at a predetermined concentration and (ii) at least one non-reactive cosolvent at a predetermined concentration; the cosolvent has a different boiling point than the propylene oxide; the propylene oxide is partitioned in a high affinity solvent during the reaction. Reacting in the presence of). The method of claim 12, wherein the method produces a waste stream in which the amount of sodium chloride (NaCl) is less than about 0.1% by weight. (a) propylene and (b) hydrogen peroxide in the presence of (c) a titanium silicalite-1 (TS-1) catalyst and (d) a predetermined amount of a mixed solvent system, wherein the mixed solvent system comprises (i) Reacting in the presence of methanol as one solvent and (ii) at least one cosolvent as the second solvent). As a method for producing propylene oxide,
(a) reacting propylene, a catalyst, a peroxide compound, an alcohol mixture and a non-reactive solvent together to form a reaction mixture, wherein the reaction mixture contents comprise two or more liquid phases and a catalyst; Simultaneously decanting the contents of the reaction mixture, wherein the liquid phase is separated from the catalyst and the liquid phase is recovered for further processing;
(b) separating the two liquid phases of step (a) from each other to form an aqueous phase and an organic phase;
(c) in at least one separation unit operation, separating the organic compound present in the aqueous phase of step (b) from the aqueous phase to form an organic compound stream and a wastewater stream;
(d) recycling the organic compound stream of step (c) to the reaction mixture; Recovering said wastewater stream of step (c) or directing it to subsequent processing operations;
(e) recovering said organic phase of step (b) comprising said non-reactive solvent, unreacted propylene and said propylene oxide in at least one working unit;
(f) separating the propylene oxide from other components of the organic phase;
(g) recovering the propylene oxide product from step (f);
(h) recycling said unreacted propylene and said non-reactive solvent stream of step (f) to said reaction mixture; And
(i) optionally purging all of the undesirable compounds accumulated in the recycle step of the process. As a method for producing propylene oxide,
(a) reacting propylene, catalyst, hydrogen peroxide, alcohol mixture and non-reactive solvent together to form a reaction mixture, wherein the reaction mixture contents comprise two or more liquid phases and a catalyst; Simultaneously decanting the reaction mixture contents, wherein the catalyst can be combined with one or more of the liquid phases; the liquid phases and the catalyst are recovered for further processing;
(b) separating the two liquid phases of step (a) from each other to form an aqueous phase and an organic phase, each or both of which may contain part of the catalyst;
(c) in at least one separation unit operation, separating the organic compound present in the aqueous phase of step (b) from the aqueous phase to form an organic compound stream and a wastewater stream;
(d) recycling the organic compound stream of step (c) to the reaction mixture; Recovering said wastewater stream of step (c) or directing it to subsequent processing operations;
(e) in at least one working unit, recovering the catalyst component present in the aqueous phase of step (b) from the aqueous phase to form a concentrated catalyst stream; Recycling the concentrated catalyst stream to the reactor or sending the concentrated catalyst stream to subsequent processing operations;
(f) recovering the organic phase of step (b) comprising at least one working unit, the non-reactive solvent, unreacted propylene, the propylene oxide and optionally, a portion of the catalyst;
(g) separating the propylene oxide from other components of the organic phase;
(h) recovering the propylene oxide product from step (g);
(i) recycling said unreacted propylene and said non-reactive solvent stream of step (g) to said reaction mixture;
(j) in at least one working unit, recovering the catalyst component present in the organic phase of step (f) from the organic phase to form a concentrated catalyst stream; Recycling the concentrated catalyst stream to the reactor or sending the concentrated catalyst stream to subsequent processing operations; And
(k) optionally, purging all of the undesirable compounds accumulated in said recycling step of said process. The method of claim 12, wherein the one or more peroxide compounds comprise hydrogen peroxide; The at least one catalyst comprises a titanium silicate catalyst; The at least one alcohol in the solvent mixture comprises methanol; Wherein said at least one non-reactive cosolvent comprises a C3-C18 straight or cyclic alkanes, halogenated hydrocarbons, inactivated aromatics, amides, solvents containing nitriles, alcohols, halogenated alcohols or mixtures thereof. The process of claim 12, wherein the reaction step is carried out in two or more reactors connected in series, and wherein the olefin and peroxide streams are counter-current flow through the reactor, cocurrent. supplied in co-current flow or cross-current flow. The method of claim 18, wherein the catalyst and liquid phases are separated in a subsequent operation.

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